JPH0240904A - Method of controlling pulse magnetizing current - Google Patents

Abstract

PURPOSE:To extend the life of a yoke coil by a method wherein the three points, i.e., the starting point, the maximum value point of current and the generating point of inverse electromotive force are detected to set up specified time as the impressing time of gate pulse. CONSTITUTION:A gate pulse generation control substrate 12 detects the three points, i.e., the starting point, the maximum value point of current and the generating point of inverse electromotive force by voltage signals inputted through the intermediary of a shunt 11 and simultaneously measures respective elapsed times. Then the proper time out of the time width from the maximum value to the generating point of the inverse electromotive force is set up by a gate pulse voltage impressing time set up volume. Through these procedures, a shunt thyristor 9 is supplied with current for the set up time to supply a yoke coil 6 with cut current.

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention suppresses the heat generation of the load due to pulsed magnetizing current (hereinafter referred to as current), and produces an appropriate and stable magnetizing current characteristic (problems in the prior art). The output circuit of a conventional magnetizer of this type is as shown in FIG. 5, which includes a capacitor 1 that stores electric charge, a thyristor 3 that serves as a switch to flow the electric charge to the yoke coil 6 of the load. The thyristor's protective coil 2
Consisting of a freewheeling diode 4 that circulates the back electromotive force generated in one circuit in the forward direction, and a current output terminal 5, the charge of the capacitor 1 that is energized by an arbitrary voltage is transferred to the thyristor 3.
By applying a pulse voltage to the gate of the thyristor 3, the thyristor 3 is turned on, and current flows through the yoke coil to generate magnetic force. The current waveform is shown in Fig. 6. The electrical energy required for magnetization by the magnetomotive force of the coil is approximately from the start of current flow to in Fig. 6 to the peak passing point t+ of the current value (M densely In addition to this, a minimum amount of time is required for the magnetic domain walls of the magnetoparallelite to move.) The current after this is mainly loss energy that is converted into heat. However, with conventional technology, it is not possible to control this current, and as all the current from 'fo to t45 is passed through the yoke coil, its temperature rises, resulting in deterioration and burnout of the yoke coil. This is the biggest cause of wire breakage and shortening the life of the coil.Moreover, changes in coil resistance due to this temperature rise directly result in changes in the magnetizing current characteristics, which cause a decrease in the magnetization level and variations in the product quality. In order to avoid this problem, should we use forced cooling methods such as air cooling or water cooling?

At present, the current countermeasure is to set intervals between energizations. However, this is only an indirect measure and cannot be called a fundamental measure, and was not effective as a method for preventing the linear expansion and heat generation of the coil itself caused by passing a large current through the coil. In addition, stronger materials such as rare earth magnets have recently been developed, and their shapes have become smaller and smaller, requiring larger currents for magnetization, and this problem has become a major obstacle in the magnetization process.

(Example 1) Pulse magnetizing current control device This device was developed to solve the above-mentioned problems, and is used by connecting to the output terminal of a conventional magnetizer. Figure).

7. Input terminal (+/-) This is a terminal to input the current of the magnetizer.

8. Shunt thyristor protection coil This is a coil (L) for protecting the di/d characteristic of the shunt thyristor.

9. Shunt thyristor This is for shunting the current of the magnetizer at a set time.

(G) It is a gate.

10, Output terminal (+/-) This is a terminal that outputs a controlled current.

11. Current transformer or current transformer (hereinafter referred to as a current transformer) This is for extracting a voltage signal from the current of the magnetizer.

12. Gate pulse generation control board While analyzing and measuring the voltage signal of the magnetizer input through the shunt 11, generates a gate pulse voltage and applies it to the gate (G) of the shunt thyristor 9 at a set time. This board has the function of

(in) This is a terminal for inputting the voltage signal of the magnetizer from the shunt 11.

(o u t) This is a terminal that outputs gate pulse voltage.

(VR) This is a volume for setting the application time (from t+ to ℃2) of the gate pulse voltage to turn on the shunt thyristor.

13. Power supply of gate pulse generation control board This is for supplying power to the gate pulse generation control board.

The above is the configuration. This input terminal 7 is connected to the output terminal 5 of the magnetizer, and the yoke coil 6, which is a load, is connected to the output terminal 10. When current flows from the magnetizer, the yoke coil 6 controls it. Current flows. The principle operation and results of this device will be explained with reference to FIGS. 1 and 2. 1st
In the figure, input terminal 7(+) is directly connected to output terminal 10(+). The output terminal 10(-) is connected to the input terminal 7(-) via a shunt 11. On the other hand, the shunt circuit is
Connect the shunt thyristor protection coil 8 and the shunt thyristor 9 in series, connect the cathode side of the shunt thyristor 9 to the (-) of the output terminal 10, and connect the shunt thyristor protection coil side to the (+) of the output terminal 10. Reference numeral 12 connected to the shunt 11 is a gate pulse generation control board, which uses the voltage signal input through the shunt 11 to determine the start of current flow to, its maximum value t+, and the point j at which back electromotive force (kickback) occurs. Detect the three points of = and measure the elapsed time at each point. Then, an appropriate time (a time during which the necessary generated magnetic field is obtained and the temperature of the yoke coil is small) out of the time range from 'f+ to tx is reset by the gate pulse voltage application time setting volume. As a result, the current flows to the shunt thyristor at the set time, and as a result, the cut current flows to the yoke coil as shown in FIG. A (■■■) and B (■■) have different loads (
yoke coil), each waveform is divided at different times.

(Embodiment 2) Pulse current control function adhered porcelain Figure 4 is an output block circuit diagram of a pulse current control function adhered porcelain in which the pulse current control method of the present invention is incorporated into the output circuit of a magnetizer. This has the advantage that the magnetizer and the principle device of the present invention are housed in the same housing, and its purpose and effect are the same as the pulse magnetizing current control device of the first embodiment.

This significantly improves the lifespan of the module. Further, since the change in resistance value of the yoke coil due to temperature rise is reduced, extremely stable magnetizing current characteristics can be obtained and uniform magnetization can be achieved. This practical value has a remarkable effect on yoke coils for rare earth magnets that require large currents, multipolar yoke coils, and yoke coils that use thin windings. Therefore, there is no need for complicated cooling methods such as water cooling or air cooling conventionally used for this type of yoke coil, and most yoke coils do not require cooling by using this device. In addition, there is no time lost in work due to intervals between energization, which leads to improved work efficiency. Figure 3 shows the same yoke coil.

This is a comparison graph of temperature rise test data.

(Effects of the invention) Due to the above-mentioned action, the unnecessary current flowing through the yoke coil is guided to the shunt circuit, thereby directly suppressing the heat generation of the yoke coil.As a result, deterioration, burnout, and disconnection of the yoke coil are prevented. York carp

[Brief explanation of the drawing]

(FIG. 1) It is a block circuit diagram of Example 1. (FIG. 2) This is an output current waveform when Example 1 is used. By varying the time of the start of the diversion. The magnetizing current from tl to t2 can be freely controlled. (FIG. 3) A comparison graph of temperature rise test data of the same yoke coil under the same conditions when Example 1 is used and when it is not used. (Figure 4) It is an output block circuit diagram of Example 2 (pulse current control function attached porcelain). (FIG. 5) It is a magnetizing current output circuit diagram of a conventional magnetizer. (Fig. 6) This is the output current waveform of a conventional magnetizer. Daiho Co., Ltd. Figure 1 (Block circuit diagram of Example 1) 5 ...... Output terminals of RI porcelain (+/-
)6 ...... Load (yoke coil) 7
...... Input terminal (+/-) 8 ...
... Shunt thyristor protection coil 9 ...
... Diversion thyristor (G) ...
・ Gate 10 ...... Output terminal (+/-) 11
...... Current shunt 12 ...... Gate pulse generation control v4 board (in) ...... Terminal for inputting the voltage signal from 11 (out )... Terminal that outputs gate pulse voltage (V R)... Gate pulse voltage application time setting volume 13...
・Example of gate pulse generation m-based power supply No. 21i! l (Output current waveform according to Example 1) ■ ■ 4th IA (Output block circuit diagram according to Example 2) 1...
・・・・・・－・ Capacitor 2 ・・・・・・・・・
Thyristor protection coil 3 Thyristor (G)... Gate gate pulse generation control board power supply Figure 3 (m degree rise test data comparison graph) ■Example Figure 5 (Output circuit diagram of conventional magnetizer) When 1 is not used Capacitor thyristor protection coil 4° ...... Sukuristor freewheeling diode output terminal (+/-) Load (magnetizing yoke coil)

Claims (1)

[Claims] In the pulsed magnetizing current output circuit, a shunt circuit consisting of a thyristor and its protective coil is connected in parallel to the load's magnetizing yoke coil (hereinafter referred to as yoke coil), and the maximum value (peak value) of the current is measured. Heat generation in the load is reduced by controlling the current from the point to the point where back electromotive force (kickback) occurs to send an appropriate current to the load and direct unnecessary current (mainly current that converts into heat) to the shunt circuit. How to maintain stable magnetizing current characteristics of the presser foot.